1. Field of the Invention
The present invention is directed to selected 4-acyl-2,6-dialkylphenol adducts of saccharides and their use as stabilizers of organic materials against oxidative degradation.
2. Description of the Prior Art
Many organic materials suffer oxidative degradation. This problem is particularly acute in plastics and other synthetic polymers where degradation may readily occur under the high temperatures normally associated with their processing. Degradation also results in such polymers after long-term aging under ambient conditions. In order to stabilize or protect these organic materials from oxidative degradation, certain antioxidant chemical additives have been incorporated into these materials either before or during processing.
It is also known to use combinations of antioxidant additives to improve oxidative stability. Certain combinations of antioxidants provide a synergistic amount of antioxidant activity. See U.S. Pat. No. 3,535,277, which issued to Miller et al on Oct. 20, 1970. Such combinations may be made by reacting together two or more antioxidant additives to form a single compound having two or more antioxidant moieties. This approach is taught in U.S. Pat. Nos. 4,413,077, which issued to Valdiserri et al on Nov. 1, 1983, and 4,414,408, which issued to Cottman on Nov. 8, 1983.
2,6-Dialkyl substituted phenols are well known in the art as antioxidant moieties. Furthermore, the reaction of such moieties with other antioxidant moieties to provide multifunctional antioxidant molecules is known. See U.S. Pat. Nos. 3,285,855, which issued to Dexter et al on Nov. 15, 1966; 3,526,668, which issued to Starnes et al on Sept. 1, 1970; and 3,975,360, which issued to Kline on Aug. 17, 1976.
These 2,6-dialkyl substituted or hindered phenolic stabilizers, while being reasonably effective stabilizers for organic materials, may have operating problems associated with them. Specifically, they are known to cause discoloration or staining to some organic materials they intend to stabilize. They also may be too readily volatilized, and, therefore, will escape from the material they are stabilizing. This will result in a lowered antioxidant level and will shorten the service life of that material.
In view of these facts, there is a need for new antioxidants or stabilizers which have improved effectiveness against oxidative degradation over a wide variety of applications.
It is therefore an object of this invention to provide a new class of relatively nondiscoloring and nonvolative hindered phenolic stabilizers for oxidizable organic materials.
These and other objects of the invention will be apparent from the following detailed description of the invention.